Energy-Absorbing Liners and Shape Conforming Layers for Use with Pro-Tective Headgear

ABSTRACT

A multilayer shell for use in the construction of protective headgear, the shell including an outer layer, an inner layer, a middle layer disposed between the outer and inner layer which resiliently compresses in response to an impact to the outer layer, and an internal liner disposed inwardly of the inner layer. The middle layer includes a plurality of compressible members, which resiliently compress to absorb the energy of a direct impact to the outer layer and resiliently shear with respect to the inner layer in response to a tangential impact to the outer layer. The inner layer includes an open configuration, which reduces the weight of the shell, provides for greater heat ventilation from the head of the user, and permits for visualization of the compressible elements. The internal liner is formed from contourable materials which enhance user fit and comfort and reduce the weight of the protective headgear without compromising user safety.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application claiming priorityto co-pending U.S. patent application Ser. No. 11/059,427, filed Feb.16, 2005, titled “Multi-Layer Air-Cushion Shell With Energy-AbsorbingLayer For Use in the Construction of Protective Headgear.” The entiretyof this co-pending patent application is incorporated by referenceherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to protective headgear. Morespecifically, the invention relates to a layered construction ofprotective headgear having an inner liner having an open configurationwhich reduces the weight of the liner and allows for greater ventilationfrom the head and an internal liner formed of head contouring materialsthat improve the fit and comfort of the headgear further reduce the riskof and protect an individual' s head from injury.

BACKGROUND INFORMATION

Concussions, also called mild traumatic brain injury, are a common,serious problem in sports known to have detrimental effects on people inthe short and long term. With respect to athletes, a concussion is atemporary and reversible neurological impairment, with or without lossof consciousness. Another definition for a concussion is a traumaticallyinduced alteration of brain function manifested by 1) an alteration ofawareness or consciousness, and 2) signs and symptoms commonlyassociated with post-concussion syndrome, such as persistent headaches,loss of balance, and memory disturbances, to list but a few. Someathletes have had their careers abbreviated because of concussions, inparticular because those who have sustained multiple concussions show agreater proclivity to further concussions and increasingly severesymptoms. Although concussions are prevalent among athletes, the studyof concussions is difficult, treatment options are virtuallynon-existent, and “return-to-play” guidelines are speculative.Accordingly, the best current solution to concussions is prevention andminimization.

Concussion results from a force being applied to the brain, usually theresult of a direct blow to the head, which results in shearing force tothe brain tissue, and a subsequent deleterious neurometabolic andneurophysiologic cascade. There are two primary types of forcesexperienced by the brain in an impact to the head, linear accelerationand rotational acceleration. Both types of acceleration are believed tobe important in causing concussions. Decreasing the magnitude ofacceleration thus decreases the force applied to the brain, andconsequently reduces the risk or severity of a concussion.

Protective headgear is well known to help protect wearers from headinjury by decreasing the magnitude of acceleration (or deceleration)experienced by their wearers. Currently marketed helmets, primarilyaddress linear forces, but generally do not diminish the rotationalforces experienced by the brain. Helmets fall generally into twocategories: single impact helmets and multiple-impact helmets.Single-impact helmets undergo permanent deformation under impact,whereas multiple-impact helmets are capable of sustaining multipleblows. Applications of single-impact helmets include, for example,bicycling and motorcycling. Participants of contact sports, such ashockey and football, use multiple-impact helmets. Both categories ofhelmets have similar construction. A semi-rigid outer shell distributesthe force of impact over a wide area and a crushable inner layer reducesthe force upon the wearer's head.

The inner layer of single-impact helmets are typically constructed offused expanded polystyrene (EPS), a polymer impregnated with a foamingagent. EPS reduces the amount of energy that reaches the head bypermanently deforming under the force of impact. To be effective againstthe impact, the inner layer must be sufficiently thick not to crushentirely throughout its thickness. A thick inner layer, however,requires a corresponding increase in the size of the outer shell, whichincreases the size and bulkiness of the helmet.

Inner layers designed for multiple-impact helmets absorb energy throughelastic and viscoelastic deformation. To absorb multiple successivehits, these helmets need to rebound quickly to return to their originalshape. Materials that rebound too quickly, however, permit some of thekinetic energy of the impact to transfer to the wearer's head. Examplesof materials with positive rebound properties, also called elasticmemory, include foamed polyurethane, expanded polypropylene, expandedpolyethylene, and foamed vinylnitrile. Although some of these materialshave desirable rebound qualities, an inner layer constructed therefrommust be sufficiently thick to prevent forceful impacts from penetratingits entire thickness. The drawback of a thick layer, as noted above, isthe resulting bulkiness of the helmet. Moreover, the energy absorbingproperties of such materials tend to diminish with increasingtemperatures, whereas the positive rebound properties diminish withdecreasing temperatures. There remains a need, therefore, for animproved helmet construction that can reduce the risk and severity ofconcussions without the aforementioned disadvantages of current helmetdesigns.

SUMMARY OF THE INVENTION

In one aspect, the invention features protective headgear comprising anouter layer having an internally facing surface, an inner layer having asurface that faces the outer layer, and a middle layer having aplurality of compressible members disposed in a fluid-containinginterstitial region bounded by the inner and outer layers. Eachcompressible member is attached to the surface of the inner layer and tothe internally facing surface of the outer layer. The protectiveheadgear of this embodiment also includes at least one passageway bywhich fluid can leave the middle layer when the protective headgearexperiences an impact.

Corresponding with this invention there is provided a method for makingprotective headgear comprising forming a multi-layered shell by forminga plurality of individually compressible members, providing an outerlayer and a inner layer, and producing a composite structure with theindividually compressible members being disposed in an interstitialregion bounded by the outer and inner layers, each compressible memberbeing attached to an internally facing surface of the outer layer and toa surface of the inner layer facing the outer layer.

In another aspect, the invention features protective headgear comprisingan outer layer having an internally facing surface, an inner layerhaving a surface that faces the outer layer, and a middle layer having aplurality of compressible members disposed in a fluid-containinginterstitial region bounded by the inner and outer layers, and aninternal liner layer disposed inwardly of the inner layer. The innerlayer has an open configuration or a non-continuous form. The internalliner layer is formed of contouring materials which enhance user fit andcomfort and reduce the weight of the protective headgear withoutcompromising user safety.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages of this invention may be betterunderstood by referring to the following description in conjunction withthe accompanying drawings, in which like numerals indicate likestructural elements and features in various figures. The drawings arenot necessarily to scale, emphasis instead being placed uponillustrating the principles of the invention.

FIG. 1 is a side view of one embodiment of a protective headgearconstructed in accordance with the present invention.

FIG. 2 is a cross-sectional view of the protective headgear of FIG. 1having a hard inner layer disposed between a compressible internal layerand a middle layer.

FIG. 3 is a side view of another embodiment of the protective headgearthe present invention.

FIG. 4 is a cross-sectional view of still another embodiment of alayered construction for protective headgear embodying the invention,the embodiment having a multi-layer shell with a plurality ofcompressible members disposed between an outer surface and an innersurface.

FIG. 5 is a diagram illustrating a method for forming a multi-layershell for use, for example, in constructing protective headgear.

FIG. 6 is a diagram illustrating an embodiment of a method for adding aninternal layer to the multilayer shell of FIG. 5.

FIG. 7A is a diagram illustrating the operation of protective headgearof the present invention during a direct impact.

FIG. 7B is a diagram illustrating the operation of protective headgearof the present invention during a tangential impact.

FIG. 8A is a diagram of one embodiment of a compressible member having ahollow chamber for holding a volume of fluid.

FIG. 8B is a diagram of a sequence illustrating simulated effects of ahigh-energy impact to the compressible member of FIG. 8A.

FIG. 8C and 8D are diagrams illustrating the stretching and bendingcapabilities of the compressible member of FIG. 8A.

FIG. 8E is a diagram of the compressible member of FIG. 8A whencompressed.

FIG. 9A is a diagram of another embodiment of a compressible member witha hollow chamber for holding a volume of fluid.

FIG. 9B is cross-sectional view of an embodiment of a shell havingopenings formed in the outer and inner layers thereof for the passage offluid.

FIG. 10A is a cross-sectional view of an embodiment of a shell having anouter shell, an inner layer, and a plurality of compressible membersdisposed therebetween.

FIG. 10B is a diagram illustrating the shell of FIG. 10A on a wearer'shead.

FIG. 10C is a diagram illustrating the operation of protective headgearof FIG. 10A during a direct impact.

FIG. 10D is a diagram illustrating the operation of protective headgearof FIG. 10A during a tangential impact.

FIG. 11A is a rear view of an embodiment of protective headgearemploying compressible members of FIG. 9A.

FIG. 11B is a cross-sectional view of an embodiment of a shell having anouter shell, an inner layer, and a plurality of compressible membersdisposed therebetween.

FIG. 12 illustrates one embodiment of the internal liner layer of thepresent invention.

FIG. 13 illustrates another embodiment of the internal liner layer ofthe present invention.

FIG. 14 illustrates a third embodiment of the internal liner layer ofthe present invention.

FIG. 15 illustrates a fourth embodiment of the internal liner layer ofthe present invention.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

The present invention relates to protective headgear designed to lessenthe amount of force that reaches the brain of the wearer from an impactto the head. The headgear includes a shell with a multilayerconstruction for cushioning the impact, thus slowing the change invelocity of the wearer's head, producing a corresponding decrease in themagnitude of acceleration or deceleration experienced by the wearer, andreducing the risk or severity of concussion. As described further below,the protective head gear may include an outer layer, an energy-absorbingmiddle layer, and an inner layer, with one or more of these layers beingconstructed of an energy-absorbing compressible material, and an innerliner layer formed of a contourable material which contours to the shapeof an individual's head. In a preferred embodiment, the compressiblematerial is a thermoplastic elastomer (TPE). In a preferred embodiment,the contourable material is a use-dependent contour form. In anotherpreferred embodiment, the contourable material is a pressure equalizingcontouring fluid. Still other embodiments may include combinations ofthese compressible and contourable materials.

Various embodiments of the energy-absorbing layer of the shell functionto provide an air cushion during an impact to the headgear. In apreferred embodiment, an impact causes air to be expelled from theenergy-absorbing layer. Protective headgear of the invention canresponds to an impact by moving in any one or combination of ways,including (1) globally compressing over a broad area of the shell, (2)locally compressing at the point of impact, (3) flexing by the outerlayer of the shell, and (4) rotating by the outer layer and theenergy-absorbing layer with respect to the inner layer.

The multi-layer constructions of the present invention can be adaptedfor use in a variety of types of protective headgear including, but notlimited to, safety helmets, motorcycle helmets, bicycle helmets, skihelmets, lacrosse helmets, hockey helmets, and football helmets, battinghelmets for baseball and softball, headgear for rock and mountainclimbers, and headgear for boxers. Other applications can includehelmets used on construction sites, in defense and militaryapplications, and for underground activities. Although the followingdescriptions focus primarily on protective headgear, it is to beunderstood that the layered construction of the systems of the presentinvention apply to other types of equipment used for sports activitiesor for other applications, e.g., face masks, elbow pads, shoulder pads,and shin pads.

FIG. 1 shows a side view of one embodiment of a protective headgear 2constructed in accordance with the present invention. Here, theprotective headgear 2 is a helmet that has an aerodynamic shape designedfor use by bicyclists. This shape is merely exemplary; it is to beunderstood that the helmet shape can vary, depending upon the particularsporting event or activity for which the helmet is designed. Further,the protective headgear of the present invention can be constructed withvarious additional features, such as a cage for a hockey helmet, a facemask for a football helmet, a visor for a motorcycle helmet, retentionstraps, chin straps, and the like.

The protective headgear, or helmet 2, of FIG. 1 includes ventilationopenings 6 near the top to permit air to flow for cooling the wearer'shead. Here, the ventilation openings 6 are teardrop shaped, eachpointing toward the rear 10 of the helmet 2 to give a visual sensationof speed. For clarity sake, the various layers of the materials used inthe construction of the helmet 2 appear in the openings 6 as a singlelayer 14. Ventilation openings can also be on the other side of thehelmet 2 (not shown) if the helmet has a symmetric design. Such openings6 are exemplary, and can have various other shapes or be omittedaltogether, depending upon the type of helmet. As will be recognized bythose skilled in the art, protective headgear constructed in accordancewith the invention may also include other types of openings, such as earholes.

FIG. 2 shows a cross section of the helmet 2 along the line A-A′ inFIG. 1. In the embodiment shown, the helmet 2 includes an outer shelllayer 20, a compressible middle layer 24, a hard inner shell layer 28,and a compressible internal liner 32. The outer shell layer 20, middlelayer 24, and inner shell layer 28 together provide an impact-absorbingshell 30. As used herein, a layer is compressible based on the relativeease with which that layer decreases in thickness in response to anapplied force. In general, compressible layers are more apt to decreasein thickness in response to an applied force than hard layers. Thecompressible layers 24, 32 can compress discernibly in response to anapplied force. In contrast, no readily discernible compression, asdefined by a readily discernible decrease in thickness, occurs if acomparable force is applied directly to the inner shell layer 28,although that layer may temporarily deform by bending. Numericalhardness values, determined according to any one of a variety ofhardness tests, such as a Shore (Durometer) Test, can be used to measurethe relative hardness of each layer. In general, compressible layersmeasure softer than hard layers.

As described in detail below, each of the layers can be constructed of alightweight material, thus contributing towards the construction of alightweight helmet. Although not drawn to scale, FIG. 2 shows oneexample of the relative thicknesses of the various layers and coating.These relative thicknesses can also depart from those shown in FIG. 2without departing from the principles of the invention. For example, abike helmet could be made with a thick inner shell layer 28 (e.g., ofexpanded polystyrene) and with a middle layer 24 of TPE that is thinnerthan the inner shell layer 28. Also, additional layers can be disposedbetween the middle layer 24 and the inner shell layer 28, or between theinternal liner 32 and the inner shell layer 28, without departing fromthe principles of the invention.

The outer shell layer 20 covers the middle layer 24 and serves variousfunctions. For example, the outer shell layer 20 can provide durabilityby protecting the helmet 2 from punctures and scratches. Other functionsinclude presenting a smooth surface for deflecting tangential impacts,waterproofing, and displaying cosmetic features such as coloring andidentifying the product brand name. In a preferred embodiment, thisouter shell layer 20 is made of a TPE material.

Beneath the outer shell layer 20, the compressible middle layer 24covers an outer surface of the inner shell layer 28. The middle layer 24attaches to the inner shell layer 28. A primary function of the middlelayer 24 is impact energy absorption. Preferably, the middle layer 24 isconstructed of a thermoplastic elastomer material.

Thermoplastic elastomers or TPEs are polymer blends or compounds, whichexhibit thermoplastic characteristics that enable shaping into afabricated article when heated above their melting temperature, andwhich possess elastomeric properties when cooled to their designedtemperature range. Accordingly, TPEs combine the beneficial propertiesof plastic and rubber, that is, TPEs are moldable and shapeable into adesired shape when heated and are compressible and stretchable whencooled. In contrast, neither thermoplastics nor conventional rubberalone exhibits this combination of properties.

To achieve satisfactory purposes, conventional rubbers must bechemically crosslinked, a process often referred to as vulcanization.This process is slow, irreversible, and results in the individualpolymer chain being linked together by covalent bonds that remaineffective at normal processing temperatures. As a result, vulcanizedrubbers do not become fluid when heated to these normal processingtemperatures (i.e., the rubber cannot be melted). When heated well abovenormal processing temperatures, vulcanized rubbers eventually decompose,resulting in the loss of substantially all useful properties. Thus,conventional vulcanized rubbers cannot be formed into useful objects byprocesses that involve the shaping of a molten material. Such processesinclude injection molding, blow molding and extrusion, and areextensively used to produce useful articles from thermoplastics.

Thermoplastics are generally not elastic when cooled and conventionalrubbers are not moldable using manufacturing processes and equipmentcurrently used for working with thermoplastics, such as injectionmolding and extrusion. These processes, however, are applicable forworking with TPEs.

Most TPEs have a common feature: they are phase-separated systems. Atleast one phase is hard and solid at room temperature and another phaseis elastomeric and fluid. Often the phases are chemically bonded byblock or graft polymerization. In other cases, a fine dispersion of thephases is apparently sufficient. The hard phase gives the TPEs theirstrength. Without the hard phase, the elastomer phase would be free toflow under stress, and the polymers would be unusable. When the hardphase is melted, or dissolved in a solvent, flow can occur and thereforethe TPE can be processed. On cooling, or upon evaporation of thesolvent, the hard phase solidifies and the TPEs regain their strength.Thus, in one sense, the hard phase of a TPE behaves similarly to thechemical crosslinks in conventional vulcanized rubbers, and the processby which the hard phase does so is often called physical crosslinking.At the same time, the elastomer phase gives elasticity and flexibilityto the TPE.

Examples of TPEs include block copolymers containing elastomeric blockschemically linked to hard thermoplastic blocks, and blends of theseblock copolymers with other materials. Suitable hard thermoplasticblocks include polystyrene blocks, polyurethane blocks, and polyesterblocks. Other examples of TPEs include blends of a hard thermoplasticwith a vulcanized elastomer, in which the vulcanized elastomer ispresent as a dispersion of small particles. These latter blends areknown as thermoplastic vulcanizates or dynamic vulcanizates.

TPEs can also be manufactured with a variety of hardness values, e.g., asoft gel or a hard 90 Shore A or greater. One characteristic of the TPEmaterial is its ability to return to its original shape after the forceagainst the helmet 2 is removed (i.e., TPE material is said to havememory). Other characteristics of TPE include its resistance to tear,its receptiveness to coloring, and its rebound resilience elasticity.Rebound resilience elasticity is the ratio of regained energy inrelation to the applied energy, and is expressed as a percentage rangingfrom 0% to 100%. A perfect energy absorber has a percentage of 0%; aperfectly elastic material has a percentage of 100%. In general, amaterial with low rebound resilience elasticity absorbs most of theapplied energy from an impacting object and retransmits little or noneof that energy. To illustrate, a steel ball that falls upon materialwith low rebound resilience elasticity experiences little or no bounce;the material absorbs the energy of the falling ball. In contrast, theball bounces substantially if it falls upon material with high reboundresilience elasticity.

Another advantage of these TPEs is that their favorable characteristicmay exist over a wide range of temperatures. Preferably, the TPEmaterial of the middle layer 24 has a glass-transition temperature ofless than −20 degrees Fahrenheit. The glass-transition temperature isthe temperature below which the material loses its soft and rubberyqualities. A TPE material with an appropriate glass-transitiontemperature can be selected for the middle layer 24 depending on theparticular application of the helmet 2 (e.g., a glass-transitiontemperature of 0 degrees Fahrenheit may be sufficient for baseballhelmets, whereas a glass transition temperature of −40 degreesFahrenheit may be needed for football and hockey helmets).

TPEs can also be formed into a variety of structures. In one embodiment,the middle layer 24 is processed into individual members, such ascylindrical columns, or other shapes such as pyramids, spheres, orcubes, allowing for independent movement of each member structure, andfor the free flow of air around the members during an impact.Preferably, the individual members each have an air-filled chamber, asdescribed in more detail below. In another embodiment, the layer has ahoneycomb structure (i.e., waffle-type). The interconnected hexagonalcells of a honeycombed structure provide impact absorption and a highstrength-to-weight ratio, which permits construction of a lightweighthelmet. The interconnected cells absorb and distribute the energy of animpact evenly throughout the structure. The honeycomb structure alsoreduces material costs because much of the material volume is made ofopen cells. This structure can be any one in which the material isformed into interconnected walls and open cells. The cells can have ashape other than hexagonal, for example, square, rectangular,triangular, and circular, without departing from the principles of theinvention.

The formation of the middle layer 24 on the inner shell layer 28 can beaccomplished using an extrusion, blow molding, casting, or injectionmolding process. The compressible middle layer 24 and inner shell layer28 can be manufactured separately and adhered together after production,or they may be manufactured as one component, with the two layers beingadhered to each other during manufacturing. TPEs bond readily to varioustypes of substrates, such as plastic, and, thus, TPEs and substrates arecommonly manufactured together. With respect to solid and foam forms ofTPE structures, the softness (or conversely, the hardness) of the middlelayer 24 can also be determined over a range of durometers. Preferably,the hardness range for these forms is between 5 and 90 on the Shore Ascale, inclusive. The thickness of the middle layer 24 can be variedwithout departing from the principles of the invention. In oneembodiment, the middle layer 24 is approximately ¼ to one inch thick.

The inner shell layer 28 is constructed of a hardened material, such asa rigid thermoplastic, a thermoplastic alloy, expanded polystyrene, or afiber-reinforced material such as fiberglass, TWINTEX®, KEVLAR®, or BPCurv™. The inner shell layer 28 operates to provide structure to thehelmet 2, penetration resistance, and impact energy distribution to theinternal liner layer 32. In one embodiment, the thickness of the innershell layer 28 is 1/16^(th) of an inch. The thickness of the inner shelllayer 28 can be varied without departing from the principles of theinvention.

The inner shell layer 28 may be constructed of a single piece ofmaterial. Alternatively, it may be non-continuous in form such that thelayer 28 includes lines, bands or arcs of material which meet atvertices and are interrupted by open spaces in a patterned form. Asdescribed in further detail below, examples of the non-continuous shapesthat the inner shell layer 28 may take include, but are not limited to,a buckeyball shape, a grid shape, a geodesic dome and a honeycomb. Amongthe benefits of non-continuous forms of the inner shell layer are thatthe weight of the shell is reduced, heat is more easily ventilated fromthe user's head through the open spaces defined by the openings, andvisualization and manual contact with the compressible elements ispermitted.

Providing another impact energy-absorbing layer, the internal linerlayer 32 contacts the wearer's head. Other functions of the internalliner 32 may include sizing, resilience, airflow, and comfort. Ingeneral, the internal liner 32 may be constructed of a thermoplasticelastomer, a foam material of, for example, approximately ½ to 1 inchthickness. It may be constructed of expanded polystyrene.

In one preferred embodiment, the internal liner 32 is constructed of ause dependent contouring foam or a pressure equalizing contouring fluid.One type of use dependent contouring foam contemplated with in the scopeof the present invention will mold permanently to the user's head, butwill do so over a period of time. Another type of this foam takes shapewhen compressed about a user's head and only changes shape whensomething (such as the force of an impact) causes it to change. Thepressure equalizing contouring fluid instantly takes shape of thecompressing element and does not rebound, or return to its originalform. Rather, it retains the shape of the element until deformed byanother compressing element, and will not rebound. Such a contouringfluid, thus, is capable of repeatedly forming a custom mold, and willretain the shape of the last element to which it is exposed. In thisembodiment, the fluid may be continued in a bladder and, because it is afluid it will equalize pressure throughout.

The compressible internal liner 32 is attached to an inner surface ofthe inner shell layer 28. The method of attachment depends upon the typeof materials used (of the inner shell layer 28 and of the internal liner32).

Embodiments of the internal liner 32 include one or more of thefollowing, either alone or in combination: thermoplastic elastomer(TPE), expanded polystyrene, expanded polypropylene, vinyl nitrile,silicone gel, silicone foam, viscoelastic or memory foam, nitrogenexpanded polyethylene foam and polyurethane foam. The thickness and typeof foam material can be varied without departing from the principles ofthe invention.

Important to the use of the helmet of the invention is for the helmet tofit properly and to remain in place during the impact. In an embodimentnot shown, the helmet extends downwards from the regions near the earsand covers the angle of the wearer's jaw. This extension may beflexible, and when used in conjunction with a chinstrap, may be drawn intightly to provide a snug fit around the jaw. FIG. 3 shows anotherembodiment of a helmet 2′ constructed in accordance with the invention.Here, the helmet 2′ is a football helmet (facemask and chinstrap notshown). This helmet 2′ illustrates a design that covers the ears and aportion of the wearer's jaw. The helmet 2′ has ventilation openings 6′near the top and on the sides of the helmet 2′ and an ear hole 8. Again,for clarity sake, the various layers of materials used in theconstruction of the helmet 2′ appear in each opening 6′ as a singlelayer 14′.

FIG. 4 shows a cross-section of an embodiment of a layered shell 30′ foruse, for example, in the construction of protective headgear. In thisembodiment, the shell 30′ has an outer layer 20′, an inner layer 28′,and a plurality of independent compressible members 50 disposed betweenthe inner and outer layers 28′, 20′. Each member 50 attaches to aninternally facing surface of the outer layer 20′ and to a surface of theinner layer 28′ that faces the outer layer 20′. Members 50 areindependent in that each individual member 50 can compress or shearindependently of the other members 50. Here, members 50 have aresilient, compressible solid or foam construction.

Members 50 can range from approximately one-eighth inch to one inch inheight and one-eighth inch to one-half inch in diameter, and need not beof uniform height or diameter. Although shown to have the shape ofcolumns, the members 50 can have a variety of shapes, for example,pyramidal, cubic, rectangular, spherical, disc-shaped, and blob-shaped.Preferably, the members 50 are constructed of TPE material (e.g., solidform, foam), although other types of compressible materials can be usedfor producing the members 50, without departing from the principles ofthe invention, provided such materials can make the members sufficientlyresilient to respond to various types of impact by leaning, stretching,shearing, and compressing.

In one embodiment, there is a spatial separation between each member 50.Referred to herein as an interstitial region 52, the spacing between themembers 50 bounded between the inner and outer layers 28′, 20′ defines avolume of fluid. As used herein, this fluid is any substance that flows,such as gas and liquid. The distance between adjacent members 50 can bedesigned so that a desired proportion of the volume of the shell 30′(e.g., >50%) is comprised of fluid. In a preferred embodiment, the fluidwithin the interstitial region 52 is air. An air-containing interstitialregion 52 provides for lightweight headgear.

In FIG. 4, the distance between the outer layer 20′ and the inner layer28′ is exaggerated in order to reveal the members 50 of the middle layer24′. (The middle layer 24′ here comprises the members 50 andinterstitial region 52). In general, the outer layer 20′ and inner layer28′ approach and may touch each other so that any gap between the layers20′, 28′ either is imperceptible or does not exist. Preferably, theouter and inner layers are not directly attached to each other at anypoint along the shell 30′. Not directly attaching the layers enables theouter layer to move during impact independently of the inner layer in ascalp-like fashion. At one or more points along the edge of the shellwhere the outer layer approaches the inner layer, an elastic adhesive oranother intervening substance or material, can be applied in between thetwo layers in order to make the layers 20′, 28′ closely approximateother. This adhesive can be an elastomeric gel (similar to rubbercement) or an adhesive strip that attaches to each layer 20′, 28′.Despite this adhesive attachment of the intervening material to eachlayer 20′, 28′, the outer layer can still move relative to the innerlayer in scalp-like fashion. Gaps may be present in this adhesive atvarious locations along the edge of the shell to permit air to escapefrom the middle layer 24′ during an impact to the shell or to enter themiddle layer 24′ when the impact is over, as described in more detailbelow.

FIG. 5 shows a method for producing the shell 30′ for use inconstructing protective headgear. According to this method, thecompressible members 50 are constructed of TPE material 54. In step 60,a TPE foam 58 is produced from the TPE material 54, as described above.At step 64, the TPE foam 58 is extruded into a desired structure 61,here, for example, columnar members. Initial construction of thecompressible members may be in the form of a chain (i.e., a singlecontinuous string of multiple members, analogous to coupling betweencars of a train). Alternatively, the compressible members may be formedtogether as a larger unit, which has an appearance analogous to that ofa rake when the TPE structure 61 is laid flat and which takes ahemispherical shape when laid onto the inner layer 28′. Other techniquesfor forming the members together can be practiced to produce the desiredstructure 61.

The TPE foam structure 61 is placed (step 68) between and attached to afirst sheet 62 of material, to serve as the inner layer 28′, and asecond sheet 63 of material to serve as the outer layer 20′. Thecompressible members may be attached to the inner layer 28′ one member50 at a time, for example, by adhesive. Alternately, each member 50 canhave a point, nozzle, stem, which can be inserted into an appropriatelyshaped opening in the inner layer 28′ to hold that member in place. Inone embodiment, the TPE foam structure 61 has a common chemicalcomponent as the sheets 62, 63 for the inner and outer layers, thusenabling chemical adhesion between the TPE foam structure and each layerduring the manufacturing process. Thus, secondary adhesives areunnecessary, although not precluded from being used, to attach the TPEfoam structure to these layers. The resulting sheet of compositestructure 65 can then be cut (step 72) and formed (step 76) into thedesired shape of the shell 30′ (only a portion of the shell beingshown).

Instead of cutting and shaping the inner, middle, and outer layerstogether, as described above, the manufacture and shaping of each of thethree layers of the shell can occur independently, and then theindependently formed layers can be adhered to one another. As anotherembodiment, the middle and inner layers can be shaped together and theouter layer independently; then, the outer layer can be adhered to themiddle layer. This embodiment can lead to the modularization of themanufacture of helmets. For instance, the interior components of ahelmet, i.e., the liner, inner layer, and middle layer, can havestandardized construction (i.e., the same appearance irrespective of thetype of sports helmet for which the interior components are to be used),with the outer sport-specific layer, which is adhered to the middlelayer, or injection molded around the interior components, providing thecustomization of the helmet for a particular sport.

As shown in FIG. 6, a compressible (e.g., foam) internal liner 32′ canthen be added (step 80) to the multilayer shell 30′. FIG. 6 shows across-section of a portion of the shell 30′ and of the internal liner32′. The internal liner 32′ is attached (e.g., with an adhesive) to aninternally facing surface of the inner layer 28′. The shape of theinternal liner 32′ conforms to the general shape of the shell 30′ and tothe shape of a wearer's head.

The shell 30′ of the invention may reduce both linear acceleration androtational acceleration experienced by the head of the headgear wearer.Linear acceleration occurs when the center of gravity of the wearer'shead becomes rapidly displaced in a linear direction, such as mightoccur when the headgear is struck from the side. Rotationalacceleration, widely believed to be a primary cause of concussion, canoccur when the head rotates rapidly around the center of gravity, suchas might occur when the headgear is struck tangentially. Most impactsimpart both types of accelerations.

FIG. 7 A illustrates an exemplary simulated operation of the shell 30′,with solid or foam members 50, undergoing a direct impact from an object100. In this example, the shell 30′ operates to reduce linearacceleration of the headgear wearer's head 104. When the object 100strikes the outer layer 20′, the members 50 directly beneath the outerlayer 20′ at the point of impact compress. The compression of the shell30′ also causes air to exit the middle layer 24′ (arrow 108) through oneor more openings at an edge of the shell 30′ where the inner and outerlayers 28′, 20′ approach each other. Air also moves through theinterstitial region away from the point of impact (arrow 110). Thecombined effects of energy-absorption by the compressible members 50 andair cushioning by the release and movement of air operate to reduce theamount of energy that reaches the wearer's head 104. When the force ofthe impact subsides, the shape and resilience of the inner and outerlayers 28′, 20′, operate to restore the shell 30′ and the compressedmembers 50 to their original shape. When returning to the originalshape, the shell 30′ in effect inhales air through each opening at theedge.

FIG. 7B illustrates an exemplary simulated operation of the shell 30′,with solid or foam members 50, undergoing a tangential impact from anobject 100. In this example, the shell 30′ operates to reduce rotationalacceleration of the wearer's head 104. When struck by an objecttangentially, the outer layer 20′ shears with respect to the inner layer28′ in a direction of motion of the object, as illustrated by arrows112. The smoothness of the outer layer 20′ can operate to reducefriction with the object 100 and, correspondingly, to reduce therotational force experienced by the shell 30′. Members 50 at the pointof impact compress to some extent and shear with the outer layer 20′. Aswith the example of FIG. 7A, the compression causes air to exit themiddle layer 24′ and to move within the interstitial region. Thecombined effects of the shearing motion of the outer layer 20′ andmembers 50, of the energy-absorbing compression of the middle layer 24′,and of the release and movement of air operate to reduce the rotationalforce reaching the wearer's head 104. The shell 30′ and members 50return to their original shape after the force of the impact subsides.

FIG. 8A shows an embodiment of a compressible member 50′ for use inconstructing the middle layer 24′ for the shell 30′ in accordance withthe invention. Embodiments of the invention can use this type of member50′ in conjunction with or instead of openings at the edge of the shell30′. Making the member 50′ of TPE material further operates to improvethe energy-absorbing effect of the shell, although other types ofcompressible materials can be used for producing the member 50′. Themember 50′ has a top surface 120, a bottom surface 124, and a sidewall128 that define a hollow internal chamber 132. The top surface 120attaches to the outer layer 20′ of the shell 74, and the bottom surface124 attaches to the inner layer 28′. The bottom surface 124 has a smallopening 136 formed therein. When the member 50′ compresses in thegeneral direction indicated by arrow 140, airflow 144, for example,exits the small opening 136.

The size of the opening 136 is designed to produce a rate-sensitiveresponse to any impact causing compression of the member 50′. Forinstance, if the application of force upon the member 50′ is gradual orof relatively low energy, the opening 136 permits sufficient air to passthrough so that the member 50′ compresses gradually and presents littleresistance against the force. For example, an individual may be able tocompress the shell of the protective headgear manually with a moderatetouch of a hand or finger, because the energy-absorbing middle layerand, in some embodiments, the outer and inner layers are made ofcompressible materials. Because the application of the force is gradual,the wearer's head is not likely to accelerate significantly and thus isless likely to experience concussion. In addition, the wearer may feelthe air being expelled from the members 50′ onto his or her head, asdescribed further below.

If, as illustrated by FIG. 8B, the application of force upon the member50′ occurs instantaneously or is of relatively high energy, the energyof impact is converted to heat, and laminar or turbulent air flowswithin the chamber 132. The size of the opening 136, which is smallrelative to the volume of air moved by the force, restricts the emissionof the turbulent or laminar air from the chamber 132 and thus causesresistance within the chamber 132. Eventually the resistance is overcomeand air flows out, but during this process, the impact energy is thusconverted to heat. This variable response, dependent upon the energyinput, is termed a rate-sensitive or a non-linear response. An advantageof this structure is that when the member 50′ compresses and empties theentire volume of air, a length of TPE material remains, which furtherabsorbs energy. This helps prevent “bottoming out”, i.e., fullycompressing so that the cushioning effect of the member 50′ is lost andthe impinging force transfers directly to the wearer's head. In additionto providing this rate-sensitive response, the member 50′ can alsostretch and bend during tangential impact similarly to the members 50described above, as illustrated by FIG. 8C and FIG. 8D.

FIG. 8E shows the embodiment of the compressible member 50′ afterbecoming compressed. Because of its resilient nature, the tendency ofthe member 50′ is to return to its uncompressed shape. The inner andouter layers 28′, 20′ to which the member 50′ is attached alsocontribute to the restoration of the member 50′ to its uncompressedshape. The tendencies of the inner and outer layers 28′, 20′ to returnto their pre-impact shape, because of their semi-rigidness andresiliency, operate to pull the member 50′ back to its uncompressedshape. Accordingly, after the force is removed from the shell 30′, themember 50′ expands in the direction indicated by arrow 150, consequentlydrawing air in through the opening 136 as indicated by arrows 144′. FIG.8F illustrates a simulated sequence of expansion of a rate-sensitivecompressible member 50′, as the force is removed.

FIG. 9A shows a cross-section of another embodiment of a rate-sensitivecompressible member 50″ that is generally rectangular in shape (i.e., astrip). The member 50″ has a top surface 160, a bottom surface 164,sidewalls 168-1, 168-2 (generally, 168), and a hollow internal chamber172. The top surface 160 attaches to the internally facing surface ofthe outer layer 20′ of the shell 30″, and the bottom surface 164attaches to a surface of the inner layer 28′. Each sidewall 168 has arespective small opening 176-1, 176-2 (generally, 176) formed therein.(Practice of the invention can be achieved with only one of thesidewalls 168 having an opening). When the member 50″ compressesgenerally in the direction indicated by arrow 180, airflows 184 exit thesmall openings 176 and pass through the interstitial region of theshell. This embodiment illustrates that a variety of shapes, forexample, disc-shaped, cylindrical, and pyramidal, can be used toimplement rate-sensitive compressible members of the invention, capableof converting impact energy to heat of turbulent or of laminar airflow.

FIG. 9B shows a cross-section of a shell 30″′ having a plurality ofrate-sensitive compressible members 50″′ disposed between the outerlayer 20′ and inner layer 28′. Each compressible member 50″′ has aplurality of openings 176 for the passage of fluid (i.e., air). Theinner layer can have an openings 200 formed therein, to permit thepassage of fluid. Fluid escaping the rate-sensitive compressible members50″′ during impact, or returning to the compressible members 50″′ afterimpact, thus have avenues for leaving and entering the shell 30″′.Embodiments of the invention can have one or more of such openings 200in addition to or instead of openings at the edge of the shell. Further,other embodiments can use such openings 200 with other types ofcompressible members (e.g., those described in FIG. 4).

FIG. 10A shows a cross-section of an embodiment of a shell 230 having anouter layer 220, an inner layer 228, and a plurality of therate-sensitive compressible members 50′ (FIG. 8A) disposed therebetween.The opening 136 of each rate-sensitive compressible member 50′ alignswith an opening (not shown) in the surface of the inner layer 228 andthrough any liner 232 so that expelled or inhaled air (arrows 210) canpass into the interior of the protective headgear. Similarly, suchopenings 136 can be on the sides of the compressible member 50′,allowing the release and return of air through the interstitial regionof the shell 230. FIG. 10B shows the shell 230, with rate-sensitivecompressible members 50′ and an internal liner 232, on the head 234 of auser.

FIG. 10C illustrates an exemplary simulated operation of the shell 230,with rate-sensitive members 50′, undergoing a direct impact from anobject 236. In this example, the shell 230 operates to reduce linearacceleration of the headgear wearer's head 234. When the object 236strikes the outer layer, the members 50′ directly beneath the outerlayer at the point of impact compress. The compression of the shell 230also causes air to exit the members 50′ (arrows 238) and enter theinterior of the headgear through the openings in the members 50′ and inthe inner layer.

FIG. 10D illustrates an exemplary simulated operation of the shell 230,with rate-sensitive compressible members 50′, undergoing a tangentialimpact from an object 236. In this example, the shell 230 operates toreduce rotational acceleration of the wearer's head 234. When struck byan object tangentially, the outer layer shears with respect to the innerlayer in a direction of motion of the object, as illustrated by arrows240. Members 50′ at the point of impact compress to some extent andshear with the outer layer. As with the example of FIG. 10C, thecompression causes air to exit the members 50′ and to enter the interiorof the headgear. The combined effects of the shearing motion of theouter layer and members 50′, of the rate-sensitive and energy-absorbingcompression of the members 50′, and of the release of air into theinterior of the headgear operate to reduce the rotational force reachingthe wearer's head 104.

As an illustration of an exemplary use of the invention, FIG. 11A showsa rear view of an embodiment of protective headgear 250 embodying theinvention. The headgear 250 includes a pattern 254 of strip-shapedmembers 50″ (FIG. 9A) disposed between outer and inner layers of theshell. FIG. 11B shows a side view of the headgear 250 with anotherpattern 258 of strip-shaped members 50″. A variety of other patterns ispossible without departing from the principles of the invention.

FIG. 12 illustrates one embodiment of the internal liner layer 32wherein the liner is non-continuous in form and is provided with abuckeyball shape. In this configuration, the inner liner layer 32 isinterspersed with hexagon and pentagon shaped cutouts.

FIG. 13 illustrates another embodiment of the internal liner layer 32wherein the liner is non-continuous in form and is provided with a gridshape, in which square openings are the prevailing pattern.

FIG. 14 illustrates a third embodiment of the internal liner layer 32wherein the liner is provided with a geodesic dome shape havingtriangular shaped cutouts. Stated another way, in this configuration,the lines of the thermoplastic are formed into triangles which meet atthe vertices.

FIG. 15 illustrates a fourth embodiment of the internal liner layer 32wherein the liner is non-continuous and is provided with a honeycomb,wherein the liner defined hexagonal shapes. Still other examples ofinner liner configurations will be recognized by those skilled in theart, including combinations of the described patterns.

While the invention has been shown and described with reference tospecific preferred embodiments, it should be understood by those skilledin the art that various changes in form and detail may be made thereinwithout departing from the spirit and scope of the invention as definedby the following claims. For example, more than one type of compressiblemember can be combined to construct a shell for a protective headgear.

1. Protective headgear, comprising: an outer layer having an internalsurface; an inner layer having a surface that faces the outer layer; amiddle layer having a plurality of compressible members disposed in afluid-containing interstitial region formed by the inner and outerlayers; and at least one passageway by which fluid can leave the middlelayer as the outer layer deforms in response to an impact on the outerlayer.
 2. The protective headgear of claim 1, wherein the at least onepassageway includes a gap between a peripheral edge of the outer layerand a peripheral edge of the inner layer to permit fluid to exit theinterstitial region in response to an impact.
 3. The protective headgearof claim 1, wherein the at least one passageway includes an opening inthe inner layer.
 4. The protective headgear of claim 3, wherein fluidthat passes through the opening in the inner layer is felt by a wearerof the protective headgear.
 5. The protective headgear of claim 1,wherein at least one of the compressible members is made ofthermoplastic elastomer (TPE) material.
 6. The protective headgear ofclaim 5, wherein the TPE material is a TPE foam.
 7. The protectiveheadgear of claim 1, wherein at least one of the compressible members isa columnar in shape.
 8. The protective headgear of claim 1, wherein atleast one of the compressible members includes a chamber for holding avolume of fluid, and the chamber includes a chamber surface having achamber opening for the passage of fluid into and out of the chamber. 9.The protective headgear of claim 8, wherein the chamber opening isadapted to produce a rate-sensitive response to the force of the impactexerted on the outer layer.
 10. The protective headgear of claim 8,wherein at least one compressible member expels fluid from the chamberthrough the chamber opening when the compressible member is compressedby the force of the impact and expands to draw fluid back into thechamber as the compressive force exerted on the outer layer ismitigated.
 11. The protective headgear of claim 8, wherein the chamberopening is aligned with an opening in the inner layer to enable thepassage of fluid through the inner layer.
 12. The protective headgear ofclaim 1, wherein the inner layer includes an internal surface, and theheadgear further comprising a compressible internal liner disposedinwardly of the internal surface of the inner layer.
 13. The protectiveheadgear of claim 1, wherein at least one compressible member includes achamber for holding a volume of fluid, and the chamber includes achamber surface having at least one chamber opening for passing fluidinto and from the interstitial region formed by the outer and innerlayers.
 14. The protective headgear of claim 1, further comprising aresilient attachment for resiliently attaching and maintaining theorientation of the outer layer with respect to the inner layer.
 15. Theprotective headgear of claim 1, wherein the outer layer shearsrotationally with respect to the inner layer as the outer layer deformsin response to the impact.
 16. A method for making protective headgear,the method comprising the steps of: forming a multilayered shell by:forming a plurality of individually compressible members; providing anouter layer and a inner layer; and producing a composite structurewherein the compressible members are disposed in an fluid-containinginterstitial region formed by the outer and inner layers such that theouter layer deforms and the compressible members correspondinglycompress in response to an impact to the outer layer.
 17. The method ofclaim 16, wherein at least one compressible member is formed ofthermoplastic elastomer material.
 18. The method of claim 17, furthercomprising the step of: introducing a chemical foaming agent into thethermoplastic elastomer material to produce compressible members made ofthermoplastic elastomer foam.
 19. The method of claim 16, furthercomprising the step of: forming at least one of the compressible membersto include a chamber for holding a volume of fluid, the chamber defininga chamber surface having at least one chamber opening for the passage offluid into and out of the chamber.
 20. The method of claim 19, furthercomprising the step of: releasing fluid through the at least one chamberopening into the interstitial region formed by the inner and outerlayers as the outer layer deforms in response to the impact to the outerlayer.
 21. The method of claim 19, further comprising the step of:aligning the at least one chamber opening with an opening of the innerlayer; and releasing fluid through the at least one chamber openingtoward the head of a wearer as the outer layer deforms in response to animpact to the outer layer.
 22. The method of claim 16, wherein theproducing step is such that the outer layer shears rotationally withrespect to the inner layer in response to the impact.
 23. The protectiveheadgear of claim 1, wherein the outer layer includes an internalsurface, the inner layer includes a surface that faces the outer layerand at least one of the plurality of compressible members is attached toat least one of the internal surface of the outer layer and the surfaceof the inner layer that faces the outer surface.
 24. The method of claim16, wherein the outer layer includes an internal surface, the innerlayer includes a surface that faces the outer layer and the methodfurther comprises the step of: attaching at least one of the pluralityof compressible members to at least one of the internal surface of theouter layer and the surface of the inner layer that faces the outerlayer.
 25. Protective headgear, comprising: a relatively thin outerlayer having an outwardly facing surface; a relatively thin inner layerhaving an area which is spaced apart from the outer layer; and a middlelayer disposed in an area formed by the outer layer and the inner layer,the middle layer comprising a plurality of compressible members; themiddle layer being adapted to resiliently compress in response to abending deformation of the outer layer to absorb energy of an impact;and the outer layer being adapted to shear with respect to the innerlayer in response to a tangential component of the impact to the outerlayer.
 26. The protective headgear of claim 25, wherein the outwardlyfacing surface of the outer layer is relatively smooth to reduce thetangential component of the impact.
 27. The protective headgear of claim25, further comprising a relatively compressible inner liner disposedinwardly of the inner layer.
 28. The protective headgear of claim 25,wherein the middle layer has a rebound resilience elasticity of aboutfifty percent (50%) or less.
 29. The protective headgear of claim 28,wherein the middle layer has a rebound resilience elasticity of abouttwenty-five percent (25%) or less.
 30. The protective headgear of claim25, wherein the plurality of compressible members are disposed in afluid-containing interstitial region bounded by the outer layer and theinner layer.
 31. The protective headgear of claim 25, wherein the outerlayer includes an internally facing surface and at least one of thecompressible members of the middle layer is attached to at least one ofa surface of the inner layer that faces the outer layer and theinternally facing surface of the outer layer.
 32. The protectiveheadgear of claim 25, further comprising at least one passageway forpassing fluid from the middle layer in response to the impact.
 33. Theprotective headgear of claim 32, wherein the at least one passagewayincludes a gap between the outer layer and the inner layer.
 34. Theprotective headgear of claim 32, wherein the at least one passagewayincludes at least one opening in the inner layer.
 35. The protectiveheadgear of claim 25, wherein at least one of the compressible membersincludes walls which define a fluid-containing internal chamber and thewalls include at least one opening to permit fluid to exit the internalchamber in response to the impact.
 36. The protective headgear of claim25, wherein at least one of the compressible members has a bellows-likesidewall construction.
 37. The protective headgear of claim 35, whereinthe walls of the compressible member have a bellows-like sidewallconstruction to facilitate compression of the compressible member inresponse to the impact.
 38. The protective headgear of claim 35, whereinthe at least one opening in the walls of the compressible member isadapted to produce a rate-sensitive response to the force of the impactexerted on the outer layer such that the compressible member compresseswith relatively little resistance when the impact is of relatively lowenergy and such that the compressible member compresses with relativelyhigh resistance when the impact force is of relatively high energy. 39.The protective headgear of claim 38, wherein the at least one opening inthe walls of the compressible member is adapted such that, when theimpact is of relatively high energy, the compressible member compresseswith sufficiently high resistance to convert energy of the impact toheat in the compressible member.
 40. The protective headgear of claim25, wherein at least one of the compressible members of the middle layercompresses in response to the bending deformation of the outer layer andresiliently shears with respect to the inner layer in response to thetangential impact component.
 41. The protective headgear of claim 25,wherein the compressible members of the middle layer have a honeycombstructure of interconnected cells.
 42. The protective headgear of claim25, wherein the compressible members of the middle layer are arranged ina pre-determined pattern between the outer layer and the inner layer.43. The protective headgear of claim 41, wherein the interconnectedcells of the honeycomb-structured middle layer are arranged in apre-determined pattern between the outer layer and the inner layer. 44.The protective headgear of claim 25, wherein the compressible membersare made of thermoplastic elastomer (TPE) material.
 45. The protectiveheadgear of claim 44, wherein the TPE material is a TPE foam.
 46. Theprotective headgear of claim 44, wherein the TPE material has aglass-transition temperature less than about minus twenty degrees (−20°)Fahrenheit.
 47. The protective headgear of claim 41, wherein thehoneycomb-structured middle layer is made of a thermoplastic elastomer(TPE) material.
 48. The protective headgear of claim 47, wherein the TPEmaterial is a TPE foam.
 49. The protective headgear of claim 47, whereinthe TPE material has a glass-transition temperature less than aboutminus twenty degrees (−20°) Fahrenheit.
 50. The protective headgear ofclaim 35, wherein the at least one opening in the at least onecompressible member permits fluid to enter the internal chambers thereofas the compressible member resiliently expands as the force of theimpact is mitigated.
 51. The protective headgear of claim 35, whereinthe inner layer includes at least one opening in communication with theleast one opening in the at least one compressible member to permitfluid exiting from the at least one compressible member when compressedto pass through the inner layer.
 52. The protective headgear of claim35, further comprising a relatively compressible inner liner layerdisposed inwardly of the inner layer and wherein the inner layer and theinner liner layer include at least one opening in communication with theleast one opening in the at least one compressible member to permitfluid exiting from the compressible member when compressed to passthrough the inner layer and the inner liner layer.
 53. The protectiveheadgear of claim 25, wherein the compressible members are independentof one another.
 54. The protective headgear of claim 25, wherein thecompressible members are interconnected.
 55. The protective headgear ofclaim 25, wherein the inner layer is of a relatively rigid thermoplasticmaterial.
 56. The protective headgear of claim 25, wherein the outerlayer is of a thermoplastic material.
 57. The protective headgear ofclaim 56, wherein the thickness of the thermoplastic material of theouter layer is such that the outer layer resiliently deforms by bendinginwardly in response to the impact.
 58. The protective headgear of claim25, wherein the bending deformation of the outer layer and thecompression of compressible members of the middle layer in response tothe impact combine to reduce linear changes of velocity of a wearer'shead due to the impact.
 59. The protective headgear of claim 25, whereinthe shearing of the outer layer with respect to the inner layer and ofthe compressible members of the middle layer in response to the impactcombine to reduce rotational changes of velocity of the wearer's headdue to the impact.
 60. The protective headgear of claim 25, wherein theouter layer includes a plurality of ventilation openings.
 61. Impactabsorbing protective headgear, comprising an inner layer; an outerlayer, the inner and outer layers having opposed surfaces; and a middlelayer comprising a plurality of compressible members, the middle layerextending between the inner and outer layers the inner and outer layersbeing at least partially coextensive so that when the outer layer isimpacted, the outer layer deflects locally in response to the impact,thereby absorbing at least some of the energy created by the impact, andat least one of the compressible members of the middle layer compressesand shears relative to the inner layer to absorb impact energy notabsorbed by the outer layer.
 62. The protective headgear of claim 61,wherein the middle layer is anchored in at least one location to theopposed surfaces of the inner layer and the outer layer, the inner andouter layers being at least partially coextensive.
 63. The protectiveheadgear of claim 61, wherein the outer layer comprises an outwardlyfacing surface and the outwardly facing surface of the outer layer isrelatively smooth to reduce the tangential component of the impact. 64.The protective headgear of claim 61, further comprising a relativelycompressible inner liner layer disposed inwardly of the inner layer. 65.The protective headgear of claim 61, wherein the middle layer has arebound resilience elasticity of about fifty percent (50%) or less. 66.The protective headgear of claim 65, wherein the middle layer has arebound resilience elasticity of about twenty-five percent (25%) orless.
 67. The protective headgear of claim 61, wherein the plurality ofcompressible members are disposed in a fluid-containing interstitialregion bounded by the outer layer and the inner layer.
 68. Theprotective headgear of claim 61, wherein at least one of thecompressible members of the middle layer is attached to a surface of theinner layer that faces the outer layer and to an internally facingsurface of the outer layer.
 69. The protective headgear of claim 61,further comprising at least one passageway by which fluid can leave themiddle layer in response to the impact.
 70. The protective headgear ofclaim 69, wherein the at least one passageway includes a gap between theouter layer and the inner layer.
 71. The protective headgear of claim69, wherein the at least one passageway includes at least one opening inthe inner layer.
 72. The protective headgear of claim 61, wherein atleast one of the compressible member includes walls which define afluid-containing internal chamber and the walls include at least oneopening to permit fluid to exit the internal chamber in response to theimpact.
 73. The protective headgear of claim 61, wherein at least one ofthe compressible members has a bellows-like sidewall construction. 74.The protective headgear of claim 72, wherein the walls of the at leastone compressible member has a bellows-like sidewall construction whichfacilitates compression of the compressible member in response to theimpact.
 75. The protective headgear of claim 72, wherein the at leastone opening in the walls of the compressible member is adapted toproduce a rate-sensitive response to the force of the impact exerted onthe outer layer such that the compressible member compresses withrelatively little resistance when the impact is of relatively low energyand such that the compressible member compresses with relatively highresistance when the impact force is of relatively high energy.
 76. Theprotective headgear of claim 75, wherein the at least one opening in thewalls of the compressible member is adapted such that, when the impactis of relatively high energy, the compressible member compresses withsufficiently high resistance to convert energy of the impact to heat inthe compressible member.
 77. The protective headgear of claim 61,wherein the middle layer has a honeycomb structure of interconnectedcells.
 78. The protective headgear of claim 61, wherein the compressiblemembers of the middle layer are arranged in a pre-determined patternbetween the outer layer and the inner layer.
 79. The protective headgearof claim 77, wherein the interconnected cells of thehoneycomb-structured middle layer are arranged in a pre-determinedpattern between the outer layer and the inner layer.
 80. The protectiveheadgear of claim 61, wherein the compressible members are made ofthermoplastic elastomer (TPE) material.
 81. The protective headgear ofclaim 80, wherein the TPE material is a TPE foam.
 82. The protectiveheadgear of claim 80, wherein the TPE material has a glass-transitiontemperature less than about minus twenty degrees (−20°) Fahrenheit. 83.The protective headgear of claim 77, wherein the honeycomb-structuredmiddle layer is made of a thermoplastic elastomer (TPE) material. 84.The protective headgear of claim 83, wherein the TPE material is a TPEfoam.
 85. The protective headgear of claim 83, wherein the TPE materialhas a glass-transition temperature less than about minus twenty degrees(−20°) Fahrenheit.
 86. The protective headgear of claim 72, wherein theat least one opening in the compressible member permits fluid to bedrawn into the internal chamber thereof as the compressible memberresiliently expands in response to mitigation of the force of theimpact.
 87. The protective headgear of claim 72, wherein the inner layerincludes at least one opening in communication with the at least oneopening in the compressible member to permit fluid exiting from thecompressible member when compressed to pass through the inner layer. 88.The protective headgear of claim 72, wherein the outer layer includes atleast one opening in communication with the at least one opening in thecompressible member to permit fluid exiting from the compressible memberwhen compressed to pass through the outer layer.
 89. The protectiveheadgear of claim 72, further comprising a relatively compressible innerliner layer disposed inwardly of the inner layer and wherein the innerlayer and the inner liner layer include at least one opening incommunication with the at least one opening in the compressible memberto permit fluid exiting from the compressible member when compressed topass through the inner layer and the inner liner layer.
 90. Theprotective headgear of claim 61, wherein the compressible members areindependent of one another.
 91. The protective headgear of claim 61,wherein the compressible members are interconnected.
 92. The protectiveheadgear of claim 91, wherein a first end of at least one of thecompressible members is attached to the outer layer and a second end ofthe at least one compressible members is attached to the inner layer.93. The protective headgear of claim 61, wherein the inner layer is of arelatively rigid thermoplastic material.
 94. The protective headgear ofclaim 61, wherein the outer layer is of a thermoplastic material. 95.The protective headgear of claim 94, wherein the thickness of thethermoplastic material of the outer layer is such that the outer layerresiliently deforms by bending inwardly in response to the impact. 96.The protective headgear of claim 61, wherein the bending deformation ofthe outer layer and the compression of the middle layer in response tothe impact combine to reduce linear changes of velocity of a wearer'shead due to the impact.
 97. The protective headgear of claim 61, whereinthe shearing of the outer layer with respect to the inner layer and thecompression of the middle layer in response to the impact combine toreduce rotational changes of velocity of the wearer's head due to theimpact.
 98. The protective headgear of claims 1, 25 or 61, wherein theinner layer is non-continuous in shape.
 99. The protective headgear ofclaim 98, wherein the inner layer has a buckey ball-like shape.
 100. Theprotective headgear of claim 98, wherein the inner layer has a grid-likeshape.
 101. The protective headgear of claim 98, wherein the inner layerhas a geodesic dome-like shape.
 102. The protective headgear of claim101, wherein the inner layer has a honeycomb-like shape.
 103. Theprotective headgear of claims 12, 27 or 64, wherein the internal lineris made of a use-dependent contouring material.
 104. The protectiveheadgear of claims 12, 27 or 64, wherein the internal liner includes apressure equalizing contouring fluid.